Background Image Placement

The top left corner of the browser is 0,0. As you move right and down the numbers increase. Negatives move outside of the browser toward the left and up.

Be sure you are using a unit of measurement.

Consider the following rule:

body {
	background: url(whatever) 100px 20px;
	background-repeat: no-repeat;
}

The image will not repeat. It will be placed 100px from the left edge of the browser window and 20px from the top edge like this.

Now this one does repeat, and the placement is not quite as evident:

body {
	background: url(whatever) 100px 20px;
	background-repeat: repeat;
}

Here the image starts 100 pixels to the left of the left border:

body {
	background: url(whatever) -100px 20px;
	background-repeat: no-repeat;
}

Again, when it repeats, it is not as apparent:

body {
	background: url(whatever) -100px 20px;
	background-repeat: repeat;
}

Now consider the rule below where there is no repeat and the image is placed 2100px from the left edge. It's so far right, we can't see it. Example

body {
	background: url(whatever) 2100px 20px;
	background-repeat: no-repeat;
}

Make it repeat and it becomes visible.

body {
	background: url(whatever) 2100px 20px;
	background-repeat: repeat;
}